<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .d1{
            width: 200px;
            height: 200px;
            background-color: #0aa1ed;
            border:5px solid #f00;
            /*设置单方向的边框*/
            border-bottom: 5px dotted blue;
            border-top: 5px dotted blue;
            /*设置原切角，值越大，越圆*/
            border-radius: 10px;
        }
        .d2{
            width: 200px;
            height: 200px;
            border:5px solid #f0f;
            padding-left: 50px;
            /*避免出现掉块现象,切换为边框盒子*/
            box-sizing: border-box;
            margin:60px;
        }
        span{
            border:5px solid red
        }
        .s2{
            padding: 50px;
        }
    </style>
</head>
<body>
<div class="d1"></div>
<div class="d2">内间距测试</div>
<span>span1</span><span class="s2">span2</span><span>span3</span>
</body>
</html>